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This diagram shows
the power that the germ theory provided to physicians and public health
leaders. The central concept, that one germ causes one disease, led to
interventions that actually stopped epidemics. For example, quarantines for
some diseases like smallpox, came to be understood as methods to prevent
person-to-person transmission of microbes. The discovery of vectors such as
water, milk, insects, and healthy human carriers permitted public health
officials to clean up water supplies, kill mosquitoes, and promote the use
of sanitary privies to attack diseases via their method of transmission. A
rudimentary understanding of immunity fostered the production of preventive
vaccines. And as a final step, studies of microbes and their life cycles
allowed the development of diagnostic tests and even some effective
therapies. Anti-diphtheria serum was the first dramatic "cure" for a
disease. Parents who had previously watched their children slowly suffocate
from diphtheria before the antiserum and watched the child recover rapidly
after being given the antiserum were astounded at the new power of medicine. |